There's absolute no way Hawkeye wouldn't be very close to accurate. It is fine in other sports.
As for the 'bad decisions are good for football' argument. Nah, that's bollocks to be honest. Things like tackles and diving are up for interpretation but balls bouncing over the line is black and white, absolutely no reason why they can't have something in place for that.
The idea that it should be the same at every level is stupid too.